Bucharest, Romania
Bucharest, Romania

Time filter

Source Type

Dimonie D.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Musat M.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Doncea S.M.,Romanian National Institute for Research and Development in Chemistry and Petrochemistry | Damian C.M.,Polytechnic University of Bucharest | And 4 more authors.
International Journal of Polymer Science | Year: 2015

The paper proves that the miscibility of some blends based on starch can be improved by finding for each of them the melt resistance to flow at which the nonstationary flow and the melt degradation are avoided and the developed shear rate homogenizes optimally the material composition. The obtained results show that, for process sensitive materials like starches, the border between good and less miscibility is so narrow that the window of melt processing conditions and the best formulation must be found for each of them. The improving of miscibility by controlling the melt resistance to flow proves to be a good method to prevent retrogradation and plasticizer leaching and so to handle the new compounds behavior during usage. © 2015 Doina Dimonie et al.


PubMed | Carol Davila University of Medicine and Pharmacy, University College Dublin, Romanian National Institute for Lasers, Plasma and Radiation Physics, Polytechnic University of Bucharest and 2 more.
Type: Journal Article | Journal: Molecules (Basel, Switzerland) | Year: 2014

Novel derivatives were prepared by reaction of aromatic amines with 2-(4-ethylphenoxymethyl)benzoyl isothiocyanate, affording the N-[2-(4-ethylphenoxymethyl) benzoyl]-N-(substituted phenyl)thiourea. Structural elucidation of these compounds was performed by IR, NMR spectroscopy and elemental analysis. The new compounds were used in combination with Fe3O4 and polyvinylpyrrolidone (PVP) for the coating of medical surfaces. In our experiments, catheter pieces were coated by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. The microbial adherence ability was investigated in 6 multi-well plates by using culture based methods. The obtained surfaces were also assessed for their cytotoxicity with respect to osteoblast cells, by using fluorescence microscopy and MTT assay. The prepared surfaces by advanced laser processing inhibited the adherence and biofilm development ability of Staphylococcus aureus and Pseudomonas aeruginosa tested strains while cytotoxic effects on the 3T3-E1 preosteoblasts embedded in layer shaped alginate hydrogels were not observed. These results suggest that the obtained medical surfaces, based on the novel thiourea derivatives and magnetic nanoparticles with a polymeric shell could represent a promising alternative for the development of new and effective anti-infective strategies.


Grumezescu V.,Polytechnic University of Bucharest | Grumezescu V.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Holban A.M.,University of Bucharest | Grumezescu A.M.,Polytechnic University of Bucharest | And 8 more authors.
Biofabrication | Year: 2014

Due to their persistence and resistance to the current therapeutic approaches, Staphylococcus aureus biofilm-associated infections represent a major cause of morbidity and mortality in the hospital environment. Since (+)-usnic acid (UA), a secondary lichen metabolite, possesses antimicrobial activity against Gram-positive cocci, including S. aureus, the aim of this study was to load magnetic polylactic-co-glycolic acid-polyvinyl alcohol (PLGA-PVA) microspheres with UA, then to obtain thin coatings using matrix-assisted pulsed laser evaporation and to quantitatively assess the capacity of the bio-nano-active modified surface to control biofilm formation by S. aureus, using a culture-based assay. The UA-loaded microspheres inhibited both the initial attachment of S. aureus to the coated surfaces, as well as the development of mature biofilms. In vitro bioevalution tests performed on the fabricated thin films revealed great biocompatibility, which may endorse them as competitive candidates for the development of improved non-toxic surfaces resistant to S. aureus colonization and as scaffolds for stem cell cultivation and tissue engineering. © 2014 IOP Publishing Ltd.


Voicu G.,Polytechnic University of Bucharest | Dogaru I.,Polytechnic University of Bucharest | Melita D.,Polytechnic University of Bucharest | Mesterca R.,Polytechnic University of Bucharest | And 12 more authors.
Journal of Nanoparticle Research | Year: 2015

This paper investigates the antimicrobial potential of nanostructured mesoporous silica (NMS) functionalized with essential oils (EOs) and antibiotics (ATBs). The NMS networks were obtained by the basic procedure from cetyltrimethylammonium bromide and tetraethyl orthosilicate in the form of granules with diameters ranging from 100 to 300 nm with an average pore diameter of 2.2 nm, as confirmed by the BET–TEM analyses. The Salvia officinalis (SO) and Coriandrum sativum (CS) EOs and the streptomycin and neomycin ATBs were loaded in the NMS pores. TG analysis was performed in order to estimate the amount of the entrapped volatile EOs. The results of the biological analyses revealed that NMS/SO and NMS/CS exhibited a very good antimicrobial activity to an extent comparable or even superior to the one triggered by ATB, and a good in vitro and in vivo biocompatibility. Due to their regular pores, high biocompatibility, antimicrobial activity, and capacity to stabilize the volatile EOs, the obtained NMS can be used as an efficient drug delivery system for further biomedical applications. © 2015, Springer Science+Business Media Dordrecht.


Duta L.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Dorcioman G.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Popescu A.C.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Mihailescu I.N.,Romanian National Institute for Lasers, Plasma and Radiation Physics | And 6 more authors.
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2012

We report on the synthesis of electrode layers by Pulsed Laser Deposition technique. We selected Nickel Oxide-8Yttria-Stabilized Zirconia as anode, La0.6Sr0.4Co0.2Fe0.δOs-B perovskite material as cathode, and Yttria doped (Ceria-a Alumina) as electrolyte. We studied electrode structure (average grain size, porosity, and grain shape), the deposition uniformity and electrode-electrolyte interfaces. The electrodes were investigated in terms of morphology (Scanning Electron Microscopy) and composition (Energy Dispersive X-ray Spectroscopy). The initial powder and the synthesized cathodes have been investigated superficially and in bulk by Mössbauer spectroscopy, in order to detect and analyse local properties. We identified the conditions for electrode layer synthesis in respect with porosity, composition, and mean grain size.


Ciupina V.,Ovidius University | Ciupina V.,University of Bucharest | Ciupina V.,Academy of Romanian Scientists | Lungu C.P.,National Institute for Laser, Plasma and Radiation Physics | And 16 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

SiC single-layer or multi-layer on C used to improve the oxidation resistance and tribological properties of C have been obtained by Thermionic Vacuum Arc (TVA) method. The 200nm thickness carbon thin films was deposed on glass or Si substrate and then 100÷500 nm thickness SiC successively layers on carbon thin film was deposed. The microstructure and mechanical characteristics of as-prepared SiC coating were investigated by Transmission Electron Microscopy (TEM, STEM), Energy Dispersive X-Ray Spectroscopy (EDS), Electron Scattering Chemical Analysis (ESCA) and tribological techniques. Samples containing SiC single-layer or multi-layer coating on carbon were investigated up to 1000°C. The results of thermal treatments reveals the increase of oxidation resistance with increase of the number of SiC layers. The mechanism of oxidation protection is based on the reaction between SiC and elemental oxygen resulting SiO2 and CO. The tribological behavior of SiC coatings was evaluated with a tribometer with ball-on-disk configuration from CSM device with 6mm diameter sapphire ball, sliding speed in dry conditions being 0.2m/s, with normal contact loads of 0.5N, 1N, 1.5N and 2N, under unlubricated conditions. The friction coefficient on SiC was compared with the friction coefficient on uncoated carbon layer. Electrical surface resistance of SiC coating on carbon at different temperatures was measured comparing the potential drop on the sample with the potential drop on a series standard resistance in constant mode. © 2013 Copyright SPIE.


Plugaru R.,National Institute for Research and Development in Microtechnologies | Plugaru N.,National Institute of Materials Physics Bucharest | Mihaiu S.,Institute of Physical Chemistry Ilie Murgulescu | Vasile E.,METAV S.A. CD
Proceedings of the International Semiconductor Conference, CAS | Year: 2010

Multi-layered Al:ZnO thin films, with wurtzite - type structure and thickness up to 120 nm, as determined by x-ray diffraction and HRTEM, were grown on Si-SiO2 and glass substrates by the sol-gel method. Fluorescence spectroscopy measurements show that 0.5 at. % Al doping determines a blue shift of the emission band observed at 387nm in the undoped material. The room temperature conductivity increases when the number of layers increases, to reach a value of 3.70 (Ω·m)-1 for a ten layer film. Results obtained by total energy first principles calculations performed on systems with chemical disorder are discussed in relationship with experimental data to account for the effect of Al on the conductivity. © 2010 IEEE.


Galca A.C.,National Institute of Materials Physics Bucharest | Stancu V.,National Institute of Materials Physics Bucharest | Husanu M.A.,National Institute of Materials Physics Bucharest | Dragoi C.,National Institute of Materials Physics Bucharest | And 4 more authors.
Applied Surface Science | Year: 2011

The paper presents the influence of pulsed laser deposition (PLD) parameters on the structural and optical properties of PZT thin films grown on platinum substrate. X-ray diffraction (XRD), spectroscopic ellipsometry (SE) and X-ray photoelectron spectroscopy (XPS) are used to determine the thin film properties. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are employed to get additional information. By changing the distance between target and substrate, different crystalline orientations of PZT are obtained. The thin film thickness and its roughness, as well as the refractive index are also influenced by the chosen distance. © 2011 Elsevier B.V. All rights reserved.


Rasleanu D.,Ovidius University | Ilie D.,Ovidius University | Ionescu V.,Ovidius University | Mocanu V.,Ovidius University | And 8 more authors.
Journal of Optoelectronics and Advanced Materials | Year: 2010

The paper presents an approach for obtaining and the characterization of several nanostructured materials with special resistive magnetic properties. The Cu and Co thin films are grown by the physical Thermionic Vacuum Arc method (TVA). Successive layers of Cu and Co were deposited on glass, silicon and ceramic substrates using tungsten crucibles containing Cu and Co metals, respectively. The morphological and structural investigations were achieved by means of electron microscopy techniques: TEM (Philips, CM120ST) and SEM. The compositional analysis of the films together with the atomic percentage determination of the constituent elements were performed by the Energy Dispersive X-ray Spectroscopy (EDS) analysis.


Rasleanu D.,Ovidius University | Ciupina V.,Ovidius University | Prodan G.,Ovidius University | Lungu C.P.,National Institute for Laser, Plasma and Radiation Physics | And 2 more authors.
Journal of Optoelectronics and Advanced Materials | Year: 2013

In this paper we present an approach of the obtaining and study of nanostructured materials with special resistive magnetic properties. The Cu and Co thin films are grown by a physical thermionic vacuum arc method (TVA). Successive layers of Cu and Co were deposited on ceramic substrates using tungsten crucibles each containing Cu and Co metals, respectively. The morphological and structural investigations were achieved by means of electron microscopy technique: TEM (Philips, CM120ST). The compositional analysis of the films was performed by an X-ray spectroscopy and correlated to the electrical resistance.

Loading METAV CD SA collaborators
Loading METAV CD SA collaborators